A detent is a means of locking or unlocking a movement and detents have been widely used in diverse applications including machinery, tools and consumer products.
Resilient engaging means which include rubber-like bodies or blocks have been disclosed in the following:
______________________________________ U.S. Pat. No. Issued Inventor(s) ______________________________________ 3,092,374 06/04/63 Kreheler 3,127,153 03/31/64 Elders 3,177,037 04/06/65 Elders 3,254,922 06/07/66 Kreheler. ______________________________________
A resilient wire spring to hold a screwdriver bit in a handle as disclosed in U.S. Pat. No. 2,483,563 issued to Rock is another type of detent means. U.S. Pat. No. 4,649,712 issued to Tate, Jr. et al discloses a spring clip for use in a thermostat. A detent means comprising a pin with a C-shaped spring attached to the head of the pin is disclosed in U.S. Pat. No. 3,587,457 issued to Morris. The C-shaped head serves as a spring to urge the pin to engage a notch in a wheel which encircles the detent means. These types of detents represent a less commonly used type of detent means.
The detent means used in tools are of a different type and are well known. Many applications of detents means for engaging a pawl in a ratchet wrench or in holding a socket to a ratchet wrench have been reported.
U.S. Pat. No. 4,781,085 issued to Fox, III, discloses a ball disposed in a radial cavity, the ball being moved by a spring activated locking bolt. Numerous other detent means have been disclosed for ratchet wrenches and other tool applications.
However, all of these detent means in tools comprise a spring which is disposed in a bore or in a retaining clip and a separate ball, plunger or pin which is in contact with and urged by the spring. The use of this type of detent means requires a preassembly process or a manual operation to assemble the spring and detent in the appropriate portion of the tool. The assembly further requires special tooling to facilitate loading of the detent means when the spring pressure is released against the detent means or else requires man hours to complete the assembly. Such operations become very expensive and labor intensive in the mass production of significant quantities of tools.
A further, and very serious, problem with the ball and spring detent means occurs during assembly and disassembly of tools in the manufacturing process or in the repairs/servicing procedures. To place the ball and spring detent means in the bore, the ball, which usually has a diameter of 5 mm or less, is balanced on the top of the spring using a pair of tweezers. The combination is then carefully inserted into the bore and the spring is compressed while still balancing the ball on the top. In the case of a detent means used with a pawl, a special wire type tool is used to keep the spring compressed while the pawl is slid over the detent means so that the spring can be maintained in the compressed mode while the special tool is removed. This is a tedious job which requires training and experience on the part of the assembly person. When disassembling a tool for repair, it is very difficult to prevent the compressed spring from violently ejecting the ball. There is a serious problem with facial and eye injuries due to the force with which the ball is expelled from the tool. This injury problem is compounded because of the dirt and grease which is usually associated with the detent means in a tool which has been used to a point where repair is needed. Also, frequently the ball is lost and time is consumed searching for the ball so that it will not be a hazard for persons walking in the work area. In addition, the ball and/or spring must be replaced, adding to the cost of the repair or assembly.
Thus, despite the use of detent means for many years, the above stated problems continue to exist and there remains a need for a single piece detent means for which no assembly is required and which can be used in existing tools.